Properties

Label 1.256.ax
Base Field $\F_{2^{8}}$
Dimension $1$
Ordinary Yes
$p$-rank $1$
Principally polarizable Yes
Contains a Jacobian Yes

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Invariants

Base field:  $\F_{2^{8}}$
Dimension:  $1$
L-polynomial:  $1 - 23 x + 256 x^{2}$
Frobenius angles:  $\pm0.244714587078$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{-55}) \)
Galois group:  $C_2$
Jacobians:  20

This isogeny class is simple and geometrically simple.

Newton polygon

This isogeny class is ordinary.

$p$-rank:  $1$
Slopes:  $[0, 1]$

Point counts

This isogeny class contains the Jacobians of 20 curves, and hence is principally polarizable:

Point counts of the abelian variety

$r$ 1 2 3 4 5 6 7 8 9 10
$A(\F_{q^r})$ 234 65520 16782714 4295098080 1099513228554 281474980048080 72057593704889754 18446744065195293120 4722366482759075043114 1208925819614265710958000

Point counts of the curve

$r$ 1 2 3 4 5 6 7 8 9 10
$C(\F_{q^r})$ 234 65520 16782714 4295098080 1099513228554 281474980048080 72057593704889754 18446744065195293120 4722366482759075043114 1208925819614265710958000

Decomposition and endomorphism algebra

Endomorphism algebra over $\F_{2^{8}}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-55}) \).
All geometric endomorphisms are defined over $\F_{2^{8}}$.

Base change

This is a primitive isogeny class.

Twists

Below is a list of all twists of this isogeny class.
TwistExtension DegreeCommon base change
1.256.x$2$(not in LMFDB)